sideLen=20;
gap=2;
gridSize=10;

for( a = [0 : gridSize-1])
{
  translate([a*sideLen+a*gap, 0, 0])
  for( a = [0 : gridSize-1])
  {
    translate([0, a*sideLen+a*gap, 0])
    cube(sideLen);
  }
}
